1. Field of the Invention
The present invention relates to HDMI type-D connectors, and more particularly, to a HDMI type-D connector with coplanar soldering portions to reduce terminal cross-talk interference and save casing space.
2. Description of the Prior Art
Due to technological advancement, the resolution of display devices is increasingly high. At present, commercially-available liquid-crystal-display televisions are usually equipped with a high-definition multimedia interface (HDMI) or a display port interface for connection with a computer or any other video device. HDMI is designed for use in transmission of fully digitalized images and sound and is effective in transmitting uncompressed audio signals and video signals. The HDMI is applicable to set-top boxes, DVD players, personal computers, video game consoles, integrated amplifiers, digital hi-fi, and TV sets. Furthermore, HDMI is effective in transmitting an audio signal and a video signal concurrently and simplifying installation of a system greatly, because the audio and video signals share the same cable.
Since its inception, HDMI has rapidly evolved into the digital interface standard of consumer electronics products worldwide. From digital TV to DVD, various HDMI interface-equipped products are in wide use worldwide, allowing consumers the opportunity for enhanced digital experiences. HDMI specifications set forth four HDMI connector types, namely HDMI type A connectors, HDMI type B connectors, HDMI type C connectors, and HDMI type-D connectors.
According to HDMI standards published by HDMI Association, a HDMI type-D connector has 19 pins, defining pin 1 as Hot Plug Detect, pin 2 as Utility, pin 3 as transition-minimized differential signaling data 2+ (TMDS Data2+), pin 4 as transition-minimized differential signaling data 2 shield (TMDS Data2 Shield), pin 5 as transition-minimized differential signaling data 2− (TMDS Data2−), pin 6 as transition-minimized differential signaling data 1+ (TMDS Data1+), pin 7 as transition-minimized differential signaling data 1 shield (TMDS Data1 Shield), pin 8 as transition-minimized differential signaling data 1− (TMDS Data1−), pin 9 as transition-minimized differential signaling data 0+ (TMDS Data0+), pin 10 as transition-minimized differential signaling data 0 shield (TMDS Data0 Shield), pin 11 as transition-minimized differential signaling data 0− (TMDS Data0−), pin 12 as transition-minimized differential signaling clock+ (TMDS Clock+), pin 13 as transition-minimized differential signaling clock shield (TMDS Clock Shield), pin 14 as transition-minimized differential signaling clock− (TMDS Clock−), pin 15 as consumer electronics control (CEC), pin 16 as display data channel/consumer electronics control ground (DDC/CEC Ground), pin 17 as serial clock (SCL), pin 18 as serial data (SDA), and pin 19 as +5V power (+5 Power).
Conductive terminals (not shown) of a conventional HDMI type-D connector are arranged on the upper and lower sides at the rear of the electrical connector, such that soldering portions of the conductive terminals of the conventional HDMI type-D connector are characterized by an upper-row and lower-row arrangement. To enable the conventional HDMI type-D connector to be connected to a circuit board, it is necessary for Surface Mount Technology (SMT) contacts to be disposed on the top side and the bottom side of the circuit board such that the circuit board can be electrically connected to the HDMI type-D connector.
Hence, the circuit board has to have two layers of layout; however, the two layers of layout add to the manufacturing costs of the circuit board. Since the conductive terminals of the conventional HDMI type-D connector are characterized by the upper-row and lower-row arrangement, they are susceptible to cross-talk interference when operating at a high frequency.
As a result, transmission quality is either compromised, or the thickness of the casing is increased to reduce the cross-talk interference.
To solve the aforesaid problems, Taiwan patent I323531 discloses an electrical connector that suppresses cross-talk and comprises: a pair of signal contact plates with contact portions placed at a first row and spaced apart by a distance; ground contact plates with contact portions placed at a second row and facing the distance, wherein terminal portions of the pair of signal contact plates and the ground contact plates are disposed at a third row, and the terminal portions of the ground contact plates are adjacent to corresponding ones of the terminal portions of the pair of signal contact plates, respectively, to thereby reduce cross-talk between adjacent contact plates.
Furthermore, Taiwan patent 540187 discloses an electrical connector assembly that reduces cross-talk interference, wherein conductor electrodes are alternately arranged on two surfaces of a base board and in the lengthwise direction of the base board. One of the conductor electrodes transmits + differential signals, and another one of conductor electrodes transmits − differential signals. The conductor electrodes which transmit + differential signals and − differential signals are disposed on the forward lateral surface of the base board. A ground electrode is disposed on the opposing lateral surface of the base board and positioned between the conductor electrode transmitting + differential signals and the conductor electrode transmitting - differential signals to prevent cross-talk.
Furthermore, Taiwan patent M369574 discloses an electrical connector with contacts comprising a first signal differential pair, a second signal differential pair, and a third signal differential pair. The first signal differential pair and the third signal differential pair flank the second signal differential pair. Adjacent differential pairs are spaced apart by a power contact or a ground contact to thereby reduce interference which might otherwise be caused by cross-talk during high-speed transmission, thereby preventing cross-talk.
Each of these disclosed connectors comprise a pair of signal terminals and a ground terminal, which are characterized by an alternate arrangement to reduce or even prevent cross-talk. However, the arrangement of the terminals of these patented connectors is intricate, and thus the structure of the die for the terminal is also intricate. Accordingly, there is a need to develop alternative designs that are capable of reducing cross-talk interference between the conductive terminals, while simultaneously reducing design costs of the circuit board and saving casing space.